Friction clutch

Abstract

A clutch cover for a friction clutch and a friction clutch, where the clutch cover forms a ring wall and the ring wall forms a plurality of circumferentially spaced radially extending plates having each a radially outer end. The ring wall also form two or more concentric annular stiffening bands extending at a radial distance from one another and including an innermost annular stiffening band. The ring wall also forms an outermost annular stiffening band, wherein the annular stiffening bands connect the radial plates to each other and having each a radial thickness that is smaller than the radial distance therebetween measured in intermediate regions of the ring wall between respectively two successive radial plates. A plurality of circumferentially spaced drive members of the friction clutch protrude axially from or can be screw connected to said radially outer ends of the radial plates.

The invention claimed is: 
     
       1. A friction clutch comprising:
 a counter-pressure member, 
 a clutch housing rotationally fixed with the counter-pressure member, 
 a pressure plate rotationally fixed with the clutch housing but movable in an axial direction of the friction clutch relative to the clutch housing, 
 at least one friction plate between the pressure plate and the counter-pressure member, 
 at least one clutch spring operative between the clutch housing and the pressure plate to urge the pressure plate towards the counter-pressure member so as to clamp the at least one friction plate between the pressure plate and the counter-pressure member,
 in which the clutch housing comprises: 
 
 a radially extending annular plate member intended to be coupled in driving engagement with an engine output shaft, 
 a clutch cover forming a radially extending ring wall positioned opposite to the annular plate member and a plurality of circumferentially spaced drive members extending axially from a radially outer region of the ring wall towards the annular plate member, wherein ends of the drive members are secured to the annular plate member,
 wherein the ring wall forms: 
 
 a plurality of circumferentially spaced radially extending plates having each a radially outer end, 
 two or more concentric annular stiffening bands extending at a radial distance from one another and including an innermost annular stiffening band and an outermost annular stiffening band,
 said annular stiffening bands connecting said radial plates to each other, wherein the annular stiffening bands each have a radial thickness that is smaller than the radial distance therebetween measured in intermediate regions of the ring wall between respectively two successive radial plates, 
 wherein said drive members protrude axially from said radially outer ends of the radial plates. 
 
 
     
     
       2. A friction clutch according to  claim 1 , wherein said radial plates form each one or more mass reduction apertures. 
     
     
       3. A friction clutch according to  claim 2 , wherein said mass reduction apertures comprise two outer through holes positioned radially outside the outermost annular stiffening band and at least one inner through hole positioned between the innermost and outermost annular stiffening bands. 
     
     
       4. A friction clutch according to  claim 1 , wherein in the intermediate region between successive radial plates the ring wall is constituted by substantially only the concentric annular stiffening bands which define a single circumferentially extending through opening therebetween. 
     
     
       5. A friction clutch according to  claim 4 , wherein said through opening creates a free radial distance between the concentric annular stiffening bands and a free circumferential distance between bordering successive radial plates in said intermediate region,
 said free radial distance between the concentric annular stiffening bands is greater than one fourth of the maximum radial extension of the radial plates, and 
 said free circumferential distance between bordering successive radial plates is greater than 50%, or greater than 75%, of the circumferential extension of the radial plates measured along a same circumference. 
 
     
     
       6. A friction clutch according to  claim 1 , wherein in the intermediate region between successive radial plates, the outermost annular stiffening band has an axial thickness larger than its radial thickness. 
     
     
       7. A friction clutch according to  claim 6 , wherein the axial thickness of the outermost annular stiffening band is selected in the group consisting of:
 from 1.5 times to 2.2 times the radial thickness, 
 two times the radial thickness. 
 
     
     
       8. A friction clutch according to  claim 1 , wherein in the intermediate region between successive radial plates, the innermost annular stiffening band has an axial thickness smaller than its radial thickness. 
     
     
       9. A friction clutch according to  claim 8 , wherein the axial thickness of the innermost annular stiffening band is selected in the group consisting of:
 from 0.7 times to 0.045 times the radial thickness, 
 half the radial thickness. 
 
     
     
       10. A friction clutch according to  claim 1 , wherein in the intermediate region between successive radial plates the outermost annular stiffening band has an axial thickness larger than an axial thickness of the innermost annular stiffening band. 
     
     
       11. A friction clutch according to  claim 10 , wherein the axial thickness of the outermost annular stiffening band is selected in the group consisting of:
 from two to four times the axial thickness of the innermost annular stiffening band, 
 three times the axial thickness of the innermost annular stiffening band. 
 
     
     
       12. A friction clutch comprising:
 a counter-pressure member, 
 a clutch housing rotationally fixed with the counter-pressure member, 
 a pressure plate rotationally fixed with the clutch housing but movable in an axial direction of the friction clutch relative to the clutch housing, 
 at least one friction plate between the pressure plate and the counter-pressure member, 
 at least one clutch spring operative between the clutch housing and the pressure plate to urge the pressure plate towards the counter-pressure member so as to clamp the at least one friction plate between the pressure plate and the counter-pressure member,
 in which the clutch housing comprises: 
 
 a radially extending annular plate member intended to be coupled in driving engagement with an engine output shaft, 
 a clutch cover forming a radially extending ring wall positioned opposite to the annular plate member, 
 a plurality of circumferentially spaced drive members extending axially toward a radially outer region of the annular plate member, wherein ends of the axially extending drive members are secured to the ring wall,
 wherein the ring wall forms: 
 
 a plurality of circumferentially spaced radially extending plates having each a radially outer end, 
 two or more concentric annular stiffening bands extending at a radial distance from one another and including an innermost annular stiffening band and an outermost annular stiffening band,
 said annular stiffening bands connecting said radial plates to each other, wherein the annular stiffening bands each have a radial thickness that is smaller than the radial distance therebetween measured in intermediate regions of the ring wall between respectively two successive radial plates, 
 wherein said drive members protrude axially from said radially outer ends of the radial plates. 
 
 
     
     
       13. A friction clutch according to  claim 12 , wherein the radial plates are arranged at a constant angular pitch and have each a radial extension, a circumferential extension and an axial thickness, wherein:
 a maximum radial extension is in the range from 5 to 8 times a maximum axial thickness, 
 a maximum circumferential extension is in the range from 4 to 6 times the maximum axial thickness. 
 
     
     
       14. A friction clutch according to  claim 12 , wherein an axial thickness of the radial plates is maximum at the radially outermost annular stiffening band and said axial thickness decreases from the radially outermost annular stiffening band towards the radially outer end and said axial thickness decreases also from the radially outermost annular stiffening band towards the radially innermost annular stiffening band. 
     
     
       15. A friction clutch according to  claim 12 , wherein a circumferential width of the radial plates increases from the radially outermost annular stiffening band towards the radially outer end, with the only exception of possible locally rounded corner regions that form a smooth transition between the radial plates and the annular stiffening bands and said circumferential width of the radial plates decreases from the radially outermost annular stiffening band towards the radially innermost annular stiffening band, with the only exception of the possible locally rounded corner regions that form a smooth transition between the radial plates and the annular stiffening bands. 
     
     
       16. A friction clutch according to  claim 12 , wherein the radial plates have each a first section spanning radially between the outermost annular stiffening band and the innermost annular stiffening band, and a second section projecting radially from the outermost annular stiffening band to the radially outer end, wherein the radial extension of the second section is greater than 50%, or in the range from 75% to 120%, or in the range from 85% to 105%, of the radial extension of the first section. 
     
     
       17. A friction clutch according to  claim 12 , wherein in the intermediate region between successive radial plates, the outermost annular stiffening band has a radial thickness in a range from 0.8 to 1.2 times a radial thickness of the innermost annular stiffening band. 
     
     
       18. A friction clutch according to  claim 12 , wherein said clutch cover is a single piece made from aluminum alloy. 
     
     
       19. A clutch cover for a friction clutch, said clutch cover forming a ring wall radially extending with respect to a clutch axis,
 wherein said ring wall forms: 
 
       a plurality of circumferentially spaced radially extending plates having each a radially outer end, 
       two or more concentric annular stiffening bands extending at a radial distance from one another and including an innermost annular stiffening band and an outermost annular stiffening band,
 said annular stiffening bands connecting said radial plates to each other and said annular stiffening bands having each a radial thickness that is smaller than the radial distance therebetween measured in intermediate regions of the ring wall between respectively two successive radial plates, 
 wherein a plurality of circumferentially spaced drive members of the friction clutch are connected to and protrude axially from or can be screw connected to said radially outer ends of the radial plates.